The term "local area network" or LAN, generally refers a communications system that provides interconnection among a number of independent computing stations within a small area. This small area is typically a single building or set of closely grouped buildings.
Some of the standards or protocols for implementing a LAN require a medium attachment unit ("MAU") that couples the computing station to the physical medium implementing the interconnection. These standards typically require an attachment unit interface ("AUI") for coupling the computing station or twisted pair interface ("TPI") to the associated MAU.
A "repeater" can be used to couple together a number of nodes or hubs to extend the size of a LAN. The repeater typically includes at least one MAU for each node or hub coupled to the repeater so that signals can be passed to and from a node or hub to any other node or hub coupled to the repeater. Typically, the repeater synchronizes, amplifies and regenerates the signals as the signals are passed through to reduce data corruption.
For example, the 10BASE-T Ethernet standard uses twisted pair wiring to provide the interconnection between computing stations, with separate transmit and receive circuits. The 10BASE-T Ethernet standard is herein incorporated by reference in its entirety. Some conventional twisted pair repeaters use external filters and buffer drivers to transmit signals on each twisted pair. Because a repeater can have several MAUs (i.e., ports to several nodes or hubs), a filter and buffer driver is needed for each port, thereby increasing the repeater's size and cost. The external filters and drivers also generate a significant amount of electro-magnetic interference ("EMI").
The 10BASE-T Ethernet standard also requires each MAU in the LAN to transmit a series of "link pulses" to confirm that the MAU is properly connected. Because each repeater has one or more MAUs, each repeater must generate link pulses between signals (i.e., data) retransmitted or received on each MAU's associated twisted pair interconnect wiring. In addition, the 10BASE-T Ethernet standard provides for data transmission in "packets" that include destination address, source address, type/length field, and a data field.